The present invention pertains to a coupling assembly for components of a fluid handling system, and, in particular, to a dry break coupling assembly which has a minimal tendency to spill conveyed fluid when disconnected.
Coupling assemblies are utilized to provide ready connection and disconnection of multiple components, such as separate hoses or a hose and a tank, of a fluid handling system. In many situations, the fluid being conveyed or retained within the fluid-handling system is potentially harmful to the environment or to the user of the coupling assembly. Such fluids include pesticides, fertilizers, gasoline or flammable fluids, and a variety of toxic substances. The coupling assemblies preferably utilized with such liquids are known as dry disconnect or dry break coupling assemblies and can be connected and disconnected with minimal or zero fluid spillage.
A variety of different types of dry disconnect coupling assemblies are already known in the art. One type of dry break coupling includes spring biased popper valves mounted in the separate coupling halves. These poppet valves are opened and closed to control fluid flow through the coupling assembly by a plunger axially shiftable within one of the coupling halves. One disadvantage of this coupling configuration is an appreciable pressure drop over the length of the coupling results from the presence of the valve elements interposed within the flow path of the fluid.
Another type of dry disconnect coupling device, such as disclosed in U.S. Pat. No. 4,664,149, is automatically opened and closed when the separate coupling halves of the coupling are connected and then disconnected. While useful in some applications, these devices are complicated in design and manufacture, which may undesirably increase their cost. Furthermore, these devices may be inconvenient to use in situations where selective control or stoppage of the fluid flow during liquid transfer is desirable.
Other types of dry disconnect coupling assemblies, such as disclosed in U.S. Pat. No. 2,440,946, utilize two interfitting rotary valve elements such as ball valves. While functional to provide a dry disconnect, known devices of this type are not without their shortcomings. In some prior art designs, the mechanical linkage by which the separate coupling halves can be connected, or the manner in which the sequencing of the opening and closing of the valves is controlled, is not especially user friendly or intuitive to a user. For example, some valves require that the separate valves first be axially shifted together and then rotated relative to one another such that the camming members on one of the valves engages complementary elements on the other valve. The operation of this connection system may be confusing to some users who need to experiment to determine which way the valves need to be rotated to effect connection and subsequent disconnection. In addition, in some valves an absent-minded user can accidentally turn on the valves when they are disconnected and an unfortunate spill of potentially harmful fluids may occur.
Thus, it would be desirable to provide a dry break coupling assembly which overcomes shortcomings of these and other prior art systems.